Abstract
A near-band-edge bluish electroluminescence (EL) band centered at around 440 nm was observed from ZnO p-i-n homojunction diodes through a semi-transparent electrode deposited on the p-type ZnO top layer. The EL peak energy coincided with the photoluminescence peak energy of an equivalent p-type ZnO layer, indicating that the electron injection from the n-type layer to the p-type layer dominates the current, giving rise to the radiative recombination in the p-type layer. The imbalance in charge injection is considered to originate from the lower majority carrier concentration in the p-type layer, which is one or two orders of magnitude lower than that in the n-type one. The current-voltage characteristics showed the presence of series resistance of several hundreds ohms, corresponding to the current spread resistance within the bottom n-type ZnO. The employment of conducting ZnO substrates may solve the latter problem.
Original language | English |
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Pages (from-to) | L643-L645 |
Journal | Japanese Journal of Applied Physics, Part 2: Letters |
Volume | 44 |
Issue number | 20-23 |
DOIs | |
Publication status | Published - 2005 |
Externally published | Yes |
Keywords
- Light-emitting diode
- Pulsed laser deposition
- Self-absorption
- Thin film
- ZnO
ASJC Scopus subject areas
- Engineering(all)
- Physics and Astronomy (miscellaneous)
- Physics and Astronomy(all)